According to Le Chatelier's Principle, what happens to a system at equilibrium when it is subjected to a change in concentration, pressure or temperature?

Question

Question

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The system will undergo a permanent change in state
The system shifts in the direction that opposes the change to re-establish equilibrium.
The system will always favour the formation of reactants.
The system remains at equilibrium without any changes.

Answer 1

The correct answer is The system shifts in the direction that opposes the change to re-establish equilibrium..

Key Points

Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change and restore equilibrium. (Source: Chemistry LibreTexts)
This principle applies to changes in concentration, pressure, and temperature. (Source: Royal Society of Chemistry)
In response to a change in concentration, the system will shift to consume the added substance or produce more of the removed substance. (Source: Khan Academy)
When pressure is altered, the equilibrium will shift towards the side with fewer or more moles of gas, depending on whether pressure is increased or decreased. (Source: BBC Bitesize)
For changes in temperature, the system will shift towards the endothermic or exothermic direction to absorb or release heat accordingly. (Source: CK-12 Foundation)

Additional Information

Dynamic Equilibrium:
- It is a state in which the forward and reverse reactions occur at the same rate, resulting in no net change in the concentrations of reactants and products. (Source: Chemguide)
Endothermic and Exothermic Reactions:
- Endothermic reactions absorb heat, while exothermic reactions release heat. (Source: National Geographic)
- The direction of shift in equilibrium depends on whether the reaction is endothermic or exothermic when temperature changes. (Source: ThoughtCo)
Concentration Changes:
- Adding more reactants or removing products will shift equilibrium towards the products side. (Source: Chem4Kids)
- Conversely, adding more products or removing reactants will shift equilibrium towards the reactants side. (Source: Chem4Kids)
Pressure Changes:
- Increasing pressure favors the side with fewer moles of gas, while decreasing pressure favors the side with more moles of gas. (Source: Chemguide)
Temperature Changes:
- Increasing temperature favors the endothermic direction, while decreasing temperature favors the exothermic direction. (Source: Chemistry LibreTexts)